<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <script src="../build/react.development.js"></script>
    <script src="../build/react-dom.development.js"></script>
    <script src="../build/babel.min.js"></script>
    <title>2_原生事件绑定</title>
  </head>
  <body>
      <button id="btn1">按钮1</button>
      <button id="btn2">按钮2</button>
      <button onclick="demo()">按钮3</button>

      <script type="text/javascript">
        const btn1 = document.getElementById('btn1')
        btn1.addEventListener('click',()=>{
          alert('按钮1被点击')
        })

        const btn2 = document.getElementById('btn2')
        btn2.onclick = ()=>{
          alert('按钮2被点击')
        }

        function demo(){
          alert('按钮3被点击')
        }

      </script>
  </body>
</html>